Publications

Power spectra of shear-waves for eighteen earthquakes from the Anza-Imperial Valley region were inverted for source, mid-path Q, site attenuation and site response. The motivation was whether differences in site attenuation (parameterized as t*, r/cQ, where r is distance along ray path near the site, c is shear velocity and Q is the quality factor that parameterizes attenuation) and site response

Although numerous Earthquake Early Warning (EEW) algorithms have been developed we still lack a detailed understanding of how often and under what circumstances useful ground motion alerts can be provided to end-users. Here we analyze the alerting performance of the PLUM, EPIC and FinDer algorithms by running them retrospectively on the seismic strong motion data of the 219 earthquakes in Japan si

Geothermal energy is a global renewable resource that has the potential to provide a significant portion of baseload energy in many regions. In the United States, it has the potential to provide 8.5% of the electric generation capacity by the middle of the century. In general, geothermal systems require heat, permeability, and water to be viable for energy generation. However, with current technol

The mission of the U.S. Geological Survey (USGS) Earthquake Science Center is to collect a wide range of data on earthquakes, faults, and crustal deformation; conduct research to increase our understanding of earthquake source processes, occurrence, and effects; and synthesize this knowledge into probabilistic seismic hazard assessments, aftershock forecasts, and ground-shaking scenarios for antic

In this paper, recent studies of recorded responses of behavior and performances of two instrumented tall buildings subjected to long-period motions from events that originate at far distances (e.g. 100-800km) are presented. Significant results indicate that (a) computed average drift ratios are substantial (~0.5%), and (b) there is permanent shift of fundamental frequencies for a tall building wh

Soil chronosequences on alpine moraine complexes have been used to help unravel the glacial histories of the eastern Sierra Nevada. The moraine sequence along Bishop Creek includes well-preserved moraines that have been previously dated using cosmogenic 36Cl surface exposure ages. The goal of this study was to interpret pedogenesis within a soil geomorphic context on these quantitatively dated mor

Advances in seismic instrumentation have enabled data to be recorded at increasing sample rates. This has in turn created a need to establish higher-frequency baselines for assessing data quality, as the widely-used New High (NHNM) and Low Noise Models (NLNM) of Peterson (1993) do not extend to frequencies above 10 Hz. To provide a baseline for higher frequencies (10-100 Hz), we examine power sp

Deformation associated with plate convergence at subduction zones is accommodated by a complex system involving fault slip and viscoelastic flow. These processes have proven difficult to disentangle. The 2010 Mw 8.8 Maule earthquake occurred close to the Chilean coast within a dense network of continuously recording Global Positioning System stations, which provide a comprehensive history of surfa

This paper presents a novel framework for system identification of bridge structures using recorded earthquake data. Bridge structures are prone to spatial variability of ground motions because they extend over relatively long distances. So, input motion measurement is a challenging task, especially for long bridges with multiple piers. Moreover, direct measurement of the bridge Foundation Input M

Seafloor pressure measurements hold promise for estimating vertical displacements from transient slow slip events on submarine faults. We assess the accuracy of pressure offset estimates that evolve over days to weeks and the confidence with which they may be attributed to tectonic deformation or to the ocean water column. One common approach to resolve this ambiguity assumes water column pressure

Ground motions have been simulated for a magnitude 9 (M9) Cascadia Subduction Zone earthquake, which will affect the Puget Lowland region, including cities underlain by the Seattle, Everett, and Tacoma sedimentary basins. The current national seismic maps do not account for the effects of these basins on the risk-targeted Maximum Considered Earthquake (MCER). The simulated motions for Seattle had

The newly constructed tallest building designed in conformance with performance-based design procedure in San Francisco, California is a 61-story building equipped with an accelerometric array that recorded the January 4, 2018 M4.4 Berkeley earthquake. The building is designed with concrete core shear walls and perimeter gravity steel columns. The earthquake records as well as on-demand recorded a